Lake Jackson Pluton (VAOl;0)

State	Virginia
Name	Lake Jackson Pluton
Geologic age	Ordovician
Original map label	Ol
Comments	Western Piedmont, Northern. From expanded explanation (ref. VA002): Lake Jackson pluton (Pavlides, 1990). Mesocratic, fine- to medium-grained, strongly-foliated and locally lineated micaceous metatonalite. Plagioclase shows alteration to fine grained white mica and granular epidote; quartz has commonly been recrystallized into granoblastic- to mosaic-textured aggregates; flattened quartz blebs along with dimensionally-aligned feldspar impart a mineral lineation locally. Biotite, epidote, chlorite, and muscovite define a discontinuous sinuous foliation. Allanite is an accessory mineral that is locally rimmed by epidote.
Primary rock type	felsic gneiss
Secondary rock type
Other rock types
Lithologic constituents	Major Metamorphic > Gneissfelsic gneiss
Map references	Digital Representation of the 1993 Geologic Map of Virginia", 2003, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, viewing software not included. This is a digital version of "Geologic Map of Virginia" published in 1993. Available from: https://www.dmme.virginia.gov/commerce/ [https://www.dmme.virginia.gov/commerce/]
Unit references	Virginia Division of Mineral Resources, 1993, Geologic Map of Virginia: Virginia Division of Mineral Resources, scale 1:500,000 Digital Representation of the 1993 Geologic Map of Virginia - expanded explanation: 2003, Commonwealth of Virginia, Department of Mines, Minerals, and Energy, Divsion of Mineral Resources, Publication 147, 85 pp Digital Representation of the 1993 Geologic Map of Virginia", 2003, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, viewing software not included. This is a digital version of "Geologic Map of Virginia" published in 1993. Available from: https://www.dmme.virginia.gov/commerce/ [https://www.dmme.virginia.gov/commerce/]
Geographic coverage	Prince William